@ -822,6 +822,17 @@ static struct ast_taskprocessor *extension_state_tps;
AST_THREADSTORAGE ( switch_data ) ;
AST_THREADSTORAGE ( extensionstate_buf ) ;
/*!
* \ brief A thread local indicating whether the current thread can run
* ' dangerous ' dialplan functions .
*/
AST_THREADSTORAGE ( thread_inhibit_escalations_tl ) ;
/*!
* \ brief Set to true ( non - zero ) to globally allow all dangerous dialplan
* functions to run .
*/
static int live_dangerously ;
/*!
\ brief ast_exten : An extension
@ -1307,6 +1318,19 @@ static int totalcalls;
static AST_RWLIST_HEAD_STATIC ( acf_root , ast_custom_function ) ;
/*!
* \ brief Extra information for an \ ref ast_custom_function holding privilege
* escalation information . Kept in a separate structure for ABI compatibility .
*/
struct ast_custom_escalating_function {
AST_RWLIST_ENTRY ( ast_custom_escalating_function ) list ;
const struct ast_custom_function * acf ;
unsigned int read_escalates : 1 ;
unsigned int write_escalates : 1 ;
} ;
static AST_RWLIST_HEAD_STATIC ( escalation_root , ast_custom_escalating_function ) ;
/*! \brief Declaration of builtin applications */
static struct pbx_builtin {
char name [ AST_MAX_APP ] ;
@ -3900,6 +3924,7 @@ struct ast_custom_function *ast_custom_function_find(const char *name)
int ast_custom_function_unregister ( struct ast_custom_function * acf )
{
struct ast_custom_function * cur ;
struct ast_custom_escalating_function * cur_escalation ;
if ( ! acf ) {
return - 1 ;
@ -3916,9 +3941,64 @@ int ast_custom_function_unregister(struct ast_custom_function *acf)
}
AST_RWLIST_UNLOCK ( & acf_root ) ;
/* Remove from the escalation list */
AST_RWLIST_WRLOCK ( & escalation_root ) ;
AST_RWLIST_TRAVERSE_SAFE_BEGIN ( & escalation_root , cur_escalation , list ) {
if ( cur_escalation - > acf = = acf ) {
AST_RWLIST_REMOVE_CURRENT ( list ) ;
break ;
}
}
AST_RWLIST_TRAVERSE_SAFE_END ;
AST_RWLIST_UNLOCK ( & escalation_root ) ;
return cur ? 0 : - 1 ;
}
/*!
* \ brief Returns true if given custom function escalates privileges on read .
*
* \ param acf Custom function to query .
* \ return True ( non - zero ) if reads escalate privileges .
* \ return False ( zero ) if reads just read .
*/
static int read_escalates ( const struct ast_custom_function * acf ) {
int res = 0 ;
struct ast_custom_escalating_function * cur_escalation ;
AST_RWLIST_RDLOCK ( & escalation_root ) ;
AST_RWLIST_TRAVERSE ( & escalation_root , cur_escalation , list ) {
if ( cur_escalation - > acf = = acf ) {
res = cur_escalation - > read_escalates ;
break ;
}
}
AST_RWLIST_UNLOCK ( & escalation_root ) ;
return res ;
}
/*!
* \ brief Returns true if given custom function escalates privileges on write .
*
* \ param acf Custom function to query .
* \ return True ( non - zero ) if writes escalate privileges .
* \ return False ( zero ) if writes just write .
*/
static int write_escalates ( const struct ast_custom_function * acf ) {
int res = 0 ;
struct ast_custom_escalating_function * cur_escalation ;
AST_RWLIST_RDLOCK ( & escalation_root ) ;
AST_RWLIST_TRAVERSE ( & escalation_root , cur_escalation , list ) {
if ( cur_escalation - > acf = = acf ) {
res = cur_escalation - > write_escalates ;
break ;
}
}
AST_RWLIST_UNLOCK ( & escalation_root ) ;
return res ;
}
/*! \internal
* \ brief Retrieve the XML documentation of a specified ast_custom_function ,
* and populate ast_custom_function string fields .
@ -4020,6 +4100,50 @@ int __ast_custom_function_register(struct ast_custom_function *acf, struct ast_m
return 0 ;
}
int __ast_custom_function_register_escalating ( struct ast_custom_function * acf , enum ast_custom_function_escalation escalation , struct ast_module * mod )
{
struct ast_custom_escalating_function * acf_escalation = NULL ;
int res ;
res = __ast_custom_function_register ( acf , mod ) ;
if ( res ! = 0 ) {
return - 1 ;
}
if ( escalation = = AST_CFE_NONE ) {
/* No escalations; no need to do anything else */
return 0 ;
}
acf_escalation = ast_calloc ( 1 , sizeof ( * acf_escalation ) ) ;
if ( ! acf_escalation ) {
ast_custom_function_unregister ( acf ) ;
return - 1 ;
}
acf_escalation - > acf = acf ;
switch ( escalation ) {
case AST_CFE_NONE :
break ;
case AST_CFE_READ :
acf_escalation - > read_escalates = 1 ;
break ;
case AST_CFE_WRITE :
acf_escalation - > write_escalates = 1 ;
break ;
case AST_CFE_BOTH :
acf_escalation - > read_escalates = 1 ;
acf_escalation - > write_escalates = 1 ;
break ;
}
AST_RWLIST_WRLOCK ( & escalation_root ) ;
AST_RWLIST_INSERT_TAIL ( & escalation_root , acf_escalation , list ) ;
AST_RWLIST_UNLOCK ( & escalation_root ) ;
return 0 ;
}
/*! \brief return a pointer to the arguments of the function,
* and terminates the function name with ' \ \ 0 '
*/
@ -4041,6 +4165,124 @@ static char *func_args(char *function)
return args ;
}
void pbx_live_dangerously ( int new_live_dangerously )
{
if ( new_live_dangerously & & ! live_dangerously ) {
ast_log ( LOG_WARNING , " Privilege escalation protection disabled! \n "
" See https://wiki.asterisk.org/wiki/x/1gKfAQ for more details. \n " ) ;
}
if ( ! new_live_dangerously & & live_dangerously ) {
ast_log ( LOG_NOTICE , " Privilege escalation protection enabled. \n " ) ;
}
live_dangerously = new_live_dangerously ;
}
int ast_thread_inhibit_escalations ( void )
{
int * thread_inhibit_escalations ;
thread_inhibit_escalations = ast_threadstorage_get (
& thread_inhibit_escalations_tl , sizeof ( * thread_inhibit_escalations ) ) ;
if ( thread_inhibit_escalations = = NULL ) {
ast_log ( LOG_ERROR , " Error inhibiting privilege escalations for current thread \n " ) ;
return - 1 ;
}
* thread_inhibit_escalations = 1 ;
return 0 ;
}
/*!
* \ brief Indicates whether the current thread inhibits the execution of
* dangerous functions .
*
* \ return True ( non - zero ) if dangerous function execution is inhibited .
* \ return False ( zero ) if dangerous function execution is allowed .
*/
static int thread_inhibits_escalations ( void )
{
int * thread_inhibit_escalations ;
thread_inhibit_escalations = ast_threadstorage_get (
& thread_inhibit_escalations_tl , sizeof ( * thread_inhibit_escalations ) ) ;
if ( thread_inhibit_escalations = = NULL ) {
ast_log ( LOG_ERROR , " Error checking thread's ability to run dangerous functions \n " ) ;
/* On error, assume that we are inhibiting */
return 1 ;
}
return * thread_inhibit_escalations ;
}
/*!
* \ brief Determines whether execution of a custom function ' s read function
* is allowed .
*
* \ param acfptr Custom function to check
* \ return True ( non - zero ) if reading is allowed .
* \ return False ( zero ) if reading is not allowed .
*/
static int is_read_allowed ( struct ast_custom_function * acfptr )
{
if ( ! acfptr ) {
return 1 ;
}
if ( ! read_escalates ( acfptr ) ) {
return 1 ;
}
if ( ! thread_inhibits_escalations ( ) ) {
return 1 ;
}
if ( live_dangerously ) {
/* Global setting overrides the thread's preference */
ast_debug ( 2 , " Reading %s from a dangerous context \n " ,
acfptr - > name ) ;
return 1 ;
}
/* We have no reason to allow this function to execute */
return 0 ;
}
/*!
* \ brief Determines whether execution of a custom function ' s write function
* is allowed .
*
* \ param acfptr Custom function to check
* \ return True ( non - zero ) if writing is allowed .
* \ return False ( zero ) if writing is not allowed .
*/
static int is_write_allowed ( struct ast_custom_function * acfptr )
{
if ( ! acfptr ) {
return 1 ;
}
if ( ! write_escalates ( acfptr ) ) {
return 1 ;
}
if ( ! thread_inhibits_escalations ( ) ) {
return 1 ;
}
if ( live_dangerously ) {
/* Global setting overrides the thread's preference */
ast_debug ( 2 , " Writing %s from a dangerous context \n " ,
acfptr - > name ) ;
return 1 ;
}
/* We have no reason to allow this function to execute */
return 0 ;
}
int ast_func_read ( struct ast_channel * chan , const char * function , char * workspace , size_t len )
{
char * copy = ast_strdupa ( function ) ;
@ -4053,6 +4295,8 @@ int ast_func_read(struct ast_channel *chan, const char *function, char *workspac
ast_log ( LOG_ERROR , " Function %s not registered \n " , copy ) ;
} else if ( ! acfptr - > read & & ! acfptr - > read2 ) {
ast_log ( LOG_ERROR , " Function %s cannot be read \n " , copy ) ;
} else if ( ! is_read_allowed ( acfptr ) ) {
ast_log ( LOG_ERROR , " Dangerous function %s read blocked \n " , copy ) ;
} else if ( acfptr - > read ) {
if ( acfptr - > mod ) {
u = __ast_module_user_add ( acfptr - > mod , chan ) ;
@ -4090,6 +4334,8 @@ int ast_func_read2(struct ast_channel *chan, const char *function, struct ast_st
ast_log ( LOG_ERROR , " Function %s not registered \n " , copy ) ;
} else if ( ! acfptr - > read & & ! acfptr - > read2 ) {
ast_log ( LOG_ERROR , " Function %s cannot be read \n " , copy ) ;
} else if ( ! is_read_allowed ( acfptr ) ) {
ast_log ( LOG_ERROR , " Dangerous function %s read blocked \n " , copy ) ;
} else {
if ( acfptr - > mod ) {
u = __ast_module_user_add ( acfptr - > mod , chan ) ;
@ -4129,11 +4375,13 @@ int ast_func_write(struct ast_channel *chan, const char *function, const char *v
char * args = func_args ( copy ) ;
struct ast_custom_function * acfptr = ast_custom_function_find ( copy ) ;
if ( acfptr = = NULL )
if ( acfptr = = NULL ) {
ast_log ( LOG_ERROR , " Function %s not registered \n " , copy ) ;
else if ( ! acfptr - > write )
} else if ( ! acfptr - > write ) {
ast_log ( LOG_ERROR , " Function %s cannot be written to \n " , copy ) ;
else {
} else if ( ! is_write_allowed ( acfptr ) ) {
ast_log ( LOG_ERROR , " Dangerous function %s write blocked \n " , copy ) ;
} else {
int res ;
struct ast_module_user * u = NULL ;
if ( acfptr - > mod )
David M. Lee
12 years ago